The Coloured Book protocols were a set of

communication protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any variation of a physical quantity. The protocol defines the rules, syntax, semantics (computer science), sem ...

s for

computer network A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or b ...

s developed in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

in the 1970s. These protocols were designed to enable communication and data exchange between different computer systems and networks. The name originated with each protocol being identified by the colour of the cover of its specification document. The protocols were in use until the 1990s when the

Internet protocol suite The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are ...

came into widespread use.

History

In the mid-1970s, the British Post Office Telecommunications division (BPO-T) worked with the academic community in the United Kingdom and the computer industry to develop a set of standards to enable interoperability among different computer systems based on the X.25 protocol suite for packet-switched

wide area network A wide area network (WAN) is a telecommunications network that extends over a large geographic area. Wide area networks are often established with leased telecommunication circuits. Businesses, as well as schools and government entities, use ...

(WAN) communication. First defined in 1975, the standards evolved through experience developing protocols for the

NPL network The NPL network, or NPL Data Communications Network, was a local area computer network operated by the National Physical Laboratory (United Kingdom), National Physical Laboratory (NPL) in London that pioneered the concept of packet switching. ...

in the late 1960s and the Experimental Packet Switched Service in the early 1970s. The Coloured Book protocols were used on SERCnet from 1980, and SWUCN from 1982, both of which became part of the

JANET Janet may refer to: Names * Janet (given name) Surname * Charles Janet (1849–1932), French engineer, inventor and biologist, known for the Left Step periodic table * Jules Janet (1861–1945), French psychologist and psychotherapist * Maur ...

academic network from 1984. The protocols were influential in the development of computer networks, particularly in the UK, gained some acceptance internationally as the first complete X.25 standard, and gave the UK "several years lead over other countries". From late 1991,

Internet protocols The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are ...

were adopted on the Janet network instead; they were operated simultaneously for a while, until X.25 support was phased out entirely in August 1997.

Protocols

The standards were defined in several documents, each addressing different aspects of computer network communication. They were identified by the colour of the cover:

Pink Book

The Pink Book defined protocols for transport over

Ethernet Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

. The protocol was basically

X.25 X.25 is an ITU-T standard protocol suite for Packet switched network, packet-switched data communication in wide area network, wide area networks (WAN). It was originally defined by the CCITT, International Telegraph and Telephone Consultative Co ...

level 3 running over LLC2.

Orange Book

The Orange Book defined protocols for transport over local networks using the

Cambridge Ring (computer network) The Cambridge Ring was an experimental local area network architecture developed at the Computer Laboratory, University of Cambridge starting in 1974 and continuing into the 1980s. It was a ring network with a theoretical limit of 255 nodes ( ...

Yellow Book

The Yellow Book defined the Yellow Book Transport Service (YBTS) protocol, also known as Network Independent Transport Service (NITS), which was mainly run over X.25. It was developed by the Data Communications Protocols Unit of the Department of Industry in the late 1970s. It could also run over TCP. The

Simple Mail Transfer Protocol The Simple Mail Transfer Protocol (SMTP) is an Internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send and receive mail messages. User-level email clients typ ...

was extended to allow running over NITS. The Yellow Book Transport Service was somewhat misnamed, as it does not fulfill the Transport role in the OSI 7-layer model. It really occupies the top of the Network layer, making up for X.25's lack of NSAP addressing at the time, which did not appear until the X.25 (1980) revision, and was not available in implementations for some years afterward. YBTS used

source routing In computer networking, source routing, also called path addressing, allows a sender of a data packet to partially or completely specify the route the packet takes through the network. In contrast, in conventional routing, routers in the network d ...

addressing between YBTS nodes—there was no global addressing scheme at that time.

Green Book

The Green Book defined two protocols to connect terminals across a network: an early version of what became Triple-X PAD running over X.25, and the TS29 protocol modelled on Triple-X PAD, but running over YBTS. It was developed by Post Office Telecommunications. These protocols are similar in functionality to

TELNET Telnet (sometimes stylized TELNET) is a client-server application protocol that provides access to virtual terminals of remote systems on local area networks or the Internet. It is a protocol for bidirectional 8-bit communications. Its main ...

Fawn Book

The Fawn Book defined the Simple Screen Management Protocol (SSMP)

Blue Book

The Blue Book defined the Network-Independent File Transfer Protocol (NIFTP), analogous to Internet

FTP The File Transfer Protocol (FTP) is a standard communication protocol used for the transfer of computer files from a server to a client on a computer network. FTP is built on a client–server model architecture using separate control and dat ...

, running over YBTS. Unlike Internet FTP, NIFTP was intended for

batch mode Batch may refer to: Food and drink * Batch (alcohol), an alcoholic fruit beverage * Batch loaf, a type of bread popular in Ireland * A dialect term for a bread roll used in North Warwickshire, Nuneaton and Coventry, as well as on the Wirral, ...

rather than

interactive Across the many fields concerned with interactivity, including information science, computer science, human-computer interaction, communication, and industrial design, there is little agreement over the meaning of the term "interactivity", but mo ...

usage.

Grey Book

The Grey Book defined protocols for

e-mail Electronic mail (usually shortened to email; alternatively hyphenated e-mail) is a method of transmitting and receiving Digital media, digital messages using electronics, electronic devices over a computer network. It was conceived in the ...

transfer (not file transfer as is sometimes claimed), running over Blue Book FTP.

Red Book

The Red Book defined the Job Transfer and Manipulation Protocol (JTMP), a mechanism for jobs to be transferred from one computer to another, and for the output to be returned to the originating (or another) computer, running over Blue Book FTP.

Legacy

Over time, as technology evolved, many of the concepts and principles from the Coloured Book Protocols were integrated into broader international standards. They remain an important part of the history and evolution of computer networking, showcasing an early effort to establish standards and protocols for efficient and reliable communication between computers. One famous quirk of Coloured Book was that components of hostnames used

reverse domain name notation Reverse domain name notation (or reverse-DNS) is a naming convention for components, packages, types or file names used by a programming language, system or framework. Reverse-DNS strings are based on registered domain names, with the order of ...

as compared to the Internet standard. For example, an address might be [email protected] instead of [email protected].

References

Sources

* *''A Dictionary of Computing''. Oxford University Press, 2004, s.v. "coloured book"

External links

alt.folklore.computers: "What is the British Grey Book protocol?"

Janet website
{{DEFAULTSORT:Coloured Book Protocols History of computing in the United Kingdom Network protocols Wide area networks X.25